players have been calling for assistant coaches for over 10 years now, and they finally have their debut this year. It appears that assistant coaches will have no influence on the team's game however, which is quite disappointing.
They will also help players with their growth and development, as well as in specific situations such as red zone or three down plays.
While coordinators certainly are influential in those areas in real life but their primary job is typically play-calling, which won't be represented in the game this year.
The screenshot indicates that Matt Nagy has an offensive and defensive playbook. If the Bears have made a change to their defensive coordinator, it will probably not impact the defense. It is possible that a team's plan could be altered due to staff sackings or hirings could be a wonderful idea, and can add diversification to the user's experience.
Capturing the game-planning aspect of football is almost impossible to capture in a realistic way, so it's tough to blame the Madden devs for choosing a system that allows in-game attribute boosts on certain kinds of play.
A good game plan doesn't necessarily improve a player's performance in specific areas of the game. rather, it puts the player in situations that make the job easier, through play-calling. My top corner won't be able to their top receiver. Even if we make an effort to pay attention to man coverage, we will never be able to play the majority of Cover 1.